Jeep xj electrical gremlin

[9nick4]

So last month or 2 I've fought this gremlin with my wiring.
The issue, out of the blue one day my volt gauge jumped to 19 volts. Normal thinking lead me to replace the computer since it regulated through it. No change, after testing my battery is NOT over charging it's sitting at 14.3 it may go up a little, but doesn't overcharge. At times I get a power surge but only a few seconds. Then another issue started with my gauges going crazy, they jump all over and shut down like jeep is off.
Parts I've replace- alternator, swapped computers, swapped clusters, chased wiring and grounds, speed sensor, cam sensor, crank sensor, unplugged battery temp sensor to see if that did anything. I'm at a loss. It does it randomly, and also makes the tranny not shift coming up to a stop it's like the trans is stuck in 3rd, won't up shift down shift nothing... any help would be awesome. Sorry for the long post I tried to upload a video but it kept saying error

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[Rusty burbin]

I have in the past purchased parts that were bad off the shelf... maybe you got a bum computer? Electrical is my Akilies heel when it comes to auto repair so I'll post this and I'll have to tap out.

Good luck though man! Sounds like a nightmare!

Oh, one more thing, my grandmother has a dodger minivan that was having similar issues but it would actually stall driving down the road. We took it to the dealership several times with no luck and then in about the 5th visit the discovered that a big part of the wire harness was melted just ever so slightly but enough to be a problem. It was wrapped up with that stuff they bundle wires up in from the factory (Idk what it's called).

They couldn't find the problem because it was wrapped up like that.

Maybe this will help you out. [emoji53]

Rustyburbin from SoCal 5 kids, wife, dog and a 1970 K20 Suburban

 

[druff6991]

I second the wiring harness thing but I also recommend looking for loose grounds.

You would be amazed of how a loose ground can mimic components going bad.

Its pain staking and requires a lot of man hours but I've seen a Cherokee roast the entire harness due to a few wires rubbing together

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[The other Sean]

Check both of your battery cables. And by that, I mean check up just past the terminals up inside the insulation. I had a car years ago that would randomly shut off for a half a second. All dash lights would shut off, gauges would drop and the engine would shut right off. one second later, all would come back on and I was good. Everything looked good and I found nothing. One day I was pulling the battery terminals off to clean some corrosion off and I noticed the positive cable had about half of the strands of wire broken just up inside the insulation. I gave the cable a bend and the terminal came off in my hand. I cut the cable straight, stripped off some insulation and re-clamped the terminal. The issue never happened again.

 

[58-fc170]

Make sure your fuses under the dash are tight and clean. In my old XJ my volt gauge would jump around and it turned out to be a corroded fuse for the gauges that was the issue. Simply cleaned up the plug in and put in a new fuse and it has been flawless for years.

 

[Rockwell]

What's the year, engine size and what things have you or anyone else changed. I can look up known problems on my computer at my shop on Monday.
As for a something to try for the weekend, un-plug then check the connector for corrosion or damaged pins then plug it back. Look close around the transmission, good luck.

 

[Rusty burbin]

A big 4 upgrade might help too.

Battery positive
Battery negative
Engine to frame ground
Alternator charge wire

Stereo shops do this all the time for big amps and speakers but I've heard of them doing it as more of a maintenance upgrade too.

I'd consider checking all the grounds first though. It's good advice! Start with the "low hanging fruit" chassis, engine, body and battery grounds would be a good starting place.

Good luck!

Rustyburbin from SoCal 5 kids, wife, dog and a 1970 K20 Suburban

 

[9nick4]

Holy cow thank you everyone for the replys!! I've been busy with work so sorry for the late response, I did forget to mention it's a 99 cherokee with the 4.0l.
I haven't been driving it due to this issue and today I kicked it down the road just to keep the battery up and I noticed when I slightly turn right I get the power surge, then as soon as I go straight it goes away and back to normal? I haven't had time to dig deep into the wiring harness and check for broke, burnt or rubbed wires. Thank you everyone who responded I didn't expect this much help! I will definitely be checking some things mentioned that I forgot to check.
I have been wanting to upgrade the electrical system with heavier gauge wiring and bigger alt, I have a sound system and lights and a winch so I know the factory charging system might not be up to par, but I've had that's upgrades for a while. I will keep everyone updated on what I find I plan to work on it tomorrow and try and find my issue, I need to get her fixed so I can hit the trails!! [emoji16]

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[9nick4]

So here's an update, replaced the battery cable ends. And chased wiring going to the trans on the passenger side. Nothing.... I've still got my issue and the frustration is getting to me. I tried to make it home from work and I believe I cooked my battery... so needless to say it's either going to a shop or a new jeep is in order [emoji17] electrical issues are my downfall and I'm throwing in the towel.

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[druff6991]

I think the Cherokee that cooked the harness that I saw, it was the bundle of wires that run through the fire wall. Like the innermost wires of the harness. I'd check there before taking it to a shop

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[9nick4]

Thank you, I'll check to see if those are messed up, I think I've spent so much time and getting frustrated that I'm going cross-eyed haha. Last night the gauges acted up for a bit then all was normal but I kept getting power surges

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